Although fatty acid synthetase and acetyl CoA carboxylase are two key enzymes affecting obesity in man, surprisingly little work has been done on these enzymes from mammalian liver. As a result, we know very little about the structure and regulation of these two enzymes from mammals. The ultimate objective of this research is to determine how the production of fatty acids is regulated in mammals. Fatty acid synthetase and acetyl CoA carboxylase, the two enzymes involved in the synthesis of fatty acids, will be purefied and characterized. Pig liver will be used as the source material, since it is likely to give results more similar to those expected in man. The characterization of the enzymes will include mol. wt. analysis of the native enzymes, dissociation of the enzymes into subunits, reassembly of the native enzymes from their component subunits, and separation of the fatty acid synthetase multienzyme complex into its seven constituent enzymes or at least into its different polypeptide chains. The studies of regulation will include analysis of the affects of various metabolites on the structure and activity of the enzymes as well as a search for possible control enzymes which modify one or both of the enzymes.